I used to have the Megashadow with a Yate H12 that did not like to be voltage controlled (so it ran 100% 24/7) and it was pretty noisy. I've been running the H100 on its lowest setting and its doing better in temps and noise is near unnoticeable- pretty much just as quiet as my TFIII and Corsair case fans.
You can def crank the fans if you want to though and they can be the noisemakers everyone has heard about. At high they are noisy and when I hooked them up directly to a 12v source they screamed. Since my temps are better then before on low, I just leave them there and enjoy the silence.